Menstrual Cyce

Question 1

Menstrual cycle

Answer 1

Included both the ovarian and uterine cycle

Question 2

Menstruation

Answer 2

Only happemd in uterine cycle

It’s basically the shedding of endometrial lining

Question 3

Ovarian cycle

Answer 3

• Pituitary gland secretes hormone fsh
• Fsh stimulates development of primary follicle in ovary into graafian follicle in the
• The developing follicle secretes hormone oestrogen
• Estrogen develops thickening tissue of endometrium which results in a thickening endometrium
• Increase in oestrogen inhabits secretion of fsh
• Increased secretion of oestrogen before 14 days stimulate pituitary gland to secrete hormone LH
• LH stimulate process of ovulation
• Under the influence of LH the ruptured follicle turns into corpus luteum
• Corpus luteum producers hormone progesterone
• Progesterone is responsible for the thickening of endometrium inhibits the release of fsh so that only one follicle mature at a time it also inhibits secretion of LH to prevent further ovulation
• After 14 days the endometrium thicken in preparation for implantation of fertilized ovum
• If fertilisation does not occur the corpus luteum starts degenerating
• The production of progesterone and oestrogen stops which leads to the endometrium breaking down causing menstruation and the secretion of fsh and LH is no longer inhibited then fsh stimulates the development of a new follicle in ovary and the process starts over again.

Question 4

What happens if fertilisation occurs

Answer 4

-If fertilisation occurs will maintain the endometrium with the PandO hormone that it secretes until the 12th week of pregnancy

Question 5

If fertilisation does not occur

Answer 5

-If fertilisation does not occur the Corpus luteum will start to degenerate which means no secretion of Pand O hormone to maintain thickening of endometrium with will cause the endometrium lining will break down.

Question 6

What is the order in which hormones will be secreted

Answer 6

F…O….L…..P

F=FSH
O=oestogen
L=LH
P=progesterone

Question 7

Why is the secretion of FSH inhibited

Answer 7

Oestrogen will stop secretion of FSH because we don’t want another follicale being developed while we have a possible egg that can be fertilised

Question 8

The negative feedback

Answer 8

This is the increase of one hormone the will decrease the release of the other hormone

• Increased levels of oestrogen secreted by development graafian follicle inhibits release of fsh prevent development of further follicle in ovary
• Increased levels in progesterone secreted by corpus luteum inhibits the release of fsh and LH this prevents further follicle development and ovulation

Once corpus luteum degenerate the progesterone and oestrogen levels in blood decrease there for secretion of fsh and LH will no longer be inhibited then the whole process starts over again